Researchers at IIT-Gandhinagar have developed a new synthetic membrane that can separate molecules differing by just a nanometer. The innovation uses a special cluster called polyoxometalate (POM), specifically a type named P8. Picture a small, rigid donut with a fixed 1 nm hole in the center. This stable size makes the cluster an ideal filter, unlike usual plastic filters which have uneven holes. Pure separation at this scale is key for clean water, carbon capture, and making medicines. The POM clusters alone formed brittle crystals, so the team added alkyl chain 'tails' to create flexible, thin films called POMbranes. Short tails left gaps, allowing faster but less precise filtering. Longer tails tightly packed, plugging the gaps so liquids only passed through the 1 nm hole. Two tail-length membranes named Q7 and Q10 blocked molecules bigger than 1 nm and allowed smaller ones to pass. These membranes could even separate molecules differing by just 100-200 daltons, ten times better than current membranes. Ketan Patel, co-author from CSIR-Central Salt and Marine Chemical Research Institute, said, "These membranes are flexible, stable across different acidity levels, and can be manufactured in large sheets." He added that these features are vital for wide industrial use. The research was published on January 13 in the Journal of the American Chemical Society, marking a promising step for precise, industrial-scale filtration technology.